Composition of immersion fluid containing contaminants

Abstract

A hydrofluoroolefin working fluid is disclosed, comprising a dielectric fluid selected from E-HFO-153-10mczz and / or E-HFO-153-10mzzy, and water dissolved in the dielectric fluid at a concentration of 10 to about 145 ppm and / or a plasticizer or plasticizer mixture dissolved in the dielectric fluid at a concentration of about 10 to about 7341 ppm. The hydrofluoroolefin working fluid is useful for immersion cooling of electronic components.

Description

Technical Field

[0001] The present invention relates to a fluid useful as a heat transfer fluid in the immersion cooling application of electrical components.

Background Art

[0002] Server components to be immersion cooled are known to be very sensitive to the presence of contaminants such as plasticizers and water. These contaminants, even in small amounts at levels less than 100 ppm, can cause hardware / server failures, shortened equipment life, or increased chip temperature. Deposits, corrosion, and dendrite formation in the immersed server portions are some of the potential specific problems described in the literature and by the industry.

[0003] Water typically comes from the server portion (exposed to moisture before being submerged in the fluid) and also from the surrounding moist air that travels towards the fluid whenever the lid of the immersion tank is open. When in solution with the immersion fluid, water can be detrimental to dielectric properties such as breakdown voltage, dielectric tangent (loss tangent), and volume resistivity. If the water concentration is higher than the solubility limit in the dielectric fluid, excess water "freezes" and can deposit on parts of the server, causing short circuits and failures. Another problem between water, especially free water, and immersion fluids such as Novec 649 and HFE-7100 is the possibility of hydrolysis - chemical decomposition of the immersion fluid - which can result in the formation of acids that can attack the server portion, causing component failures and shortening the server life.

[0004] Other typical contaminants, such as plasticizers like DOTP and TOTM, are naturally extracted (or diffused) from components such as cables, elastomers, and plastics by the immersion fluid itself. When in solution, plasticizers can be detrimental to the dielectric properties of the immersion fluid. If the plasticizer concentration is higher than the solubility limit in the dielectric fluid, excess plasticizer can deposit on the tank or server components. More specifically, these plasticizers can deposit by distillation on a hot, actively boiling surface. This can be particularly problematic for boiler plates (heat spreaders with porous heat transfer surfaces located above CPUs and GPUs) where plasticizer can deposit and fill nucleation cavities. This reduction in nucleation sites leads to decreased heat transfer performance, resulting in increased internal chip ("junction") temperatures. Higher junction temperatures reduce chip lifespan and can cause premature "throttling" (reduced processing speed) of the chip when the junction temperature approaches the maximum value established by the chip manufacturer, thereby reducing dissipated power.

[0005] If water and / or plasticizers are present in a particular immersion fluid, further chemical reactions may occur, potentially forming other compounds, which could lead to further problems in the server.

[0006] To mitigate the effects of water, plasticizers, and other contaminants, immersion cooling tanks have filtration and desiccant systems. The filtration system typically consists of a pump (or multiple pumps) that circulates the immersion fluid through a filter. Filter materials are typically activated carbon and alumina to capture plasticizers and acids. The higher the sensitivity of the immersion fluid to contaminants, i.e., the lower the acceptable ppm level of plasticizer before it begins to affect the reliability of the server, the greater the amount of sorbent medium, such as activated carbon, used, and potentially the higher the pump flow rate. More carbon means higher costs and larger filter housings. Higher flow rates mean larger pumps and higher energy consumption. Typical desiccant materials such as silica gel, molecular sieves, and calcium sulfate are used to remove moisture. Fans are used to circulate a mixture of immersion fluid vapor and air through the desiccant material. Similar to plasticizers, the higher the sensitivity of the immersion fluid to water, the more desiccant material is required, potentially the larger the fan, and the higher the cost and energy use. When the desiccant or filter material becomes saturated, it needs to be replaced. The more frequently this happens, the higher the operating costs. [Overview of the Initiative] [Means for solving the problem]

[0007] In one embodiment, a hydrofluoroolefin working fluid useful for immersion cooling is disclosed, comprising a dielectric fluid selected from the group consisting of E-HFO-153-10mczz, E-HFO-153-10mzzy, and combinations thereof, at least one of about 10 ppm to about 145 ppm of water (dissolved in the dielectric fluid) and about 10 to about 2000 ppm of a plasticizer or plasticizer mixture (dissolved in the dielectric fluid), and optionally other common contaminants. Despite the presence of water and / or plasticizer, the dielectric constant of the fluid remains less than 2.0, and in another embodiment, remains less than 1.8. In one embodiment, the dielectric loss tangent of the fluid at 20 GHz is less than 8.0E-03. In another embodiment, the dielectric loss tangent of the fluid at 20 GHz is less than 2.5E-03.

[0008] In one embodiment, an immersion cooling unit is provided that includes an immersion cell defining an internal cavity. Electronic or electrical components are located within the internal cavity. A dielectric working fluid partially fills the internal cavity and at least partially immerses the heat-generating electronic or electrical device. A condenser, such as a condensing coil, is located inside the cavity above the dielectric working fluid.

[0009] The dielectric working fluid comprises at least one of 1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene (HFO-153-10mczz) and 1,1,1,4,5,5,5-heptafluoro-4-trifluoromethyl-2-pentene (HFO-153-10mzzy), about 10 ppm to about 145 ppm of water, and at least one of about 10 to about 2000 ppm of a plasticizer or plasticizer mixture. In another embodiment, the working fluid essentially consists of at least one of 1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene (HFO-153-10mczz) and 1,1,1,4,5,5,5-heptafluoro-4-trifluoromethyl-2-pentene (HFO-153-10mzzy), about 10 ppm to about 145 ppm of water, and at least one of about 10 to about 2000 ppm of a plasticizer or plasticizer mixture.

[0010] Other features and advantages of the present invention will become apparent from the following more detailed description, which is made in conjunction with the accompanying drawings illustrating the principles of the present invention as an example. [Modes for carrying out the invention]

[0011] Large-scale computer server systems perform significant workloads and can generate a large amount of heat during operation. The majority of this heat originates from its operation. Partly due to the amount of heat generated, these systems are typically mounted in a stacked configuration with large internal cooling fans and heat dissipation fins. As the size and density of these systems increase, the thermal challenges become even greater, eventually exceeding the capacity of forced air systems.

[0012] Two-phase immersion cooling is a novel cooling technology for the high-performance cooling market, such as for applications in high-performance server systems. This cooling technology relies on the heat absorbed in the process of vaporizing an immersion fluid into a gas. The fluid used in this application must meet certain requirements to be viable during operation. For example, the boiling point of the fluid should be in the range of 30 to 75°C. Generally, this range is suitable for keeping server components at a sufficiently cool temperature while allowing the generated heat to be adequately dissipated to an external heat sink. Alternatively, the operating temperature of the server and immersion cooling system can be increased or decreased by using a sealed system and increasing or decreasing the pressure within the system to raise or decrease the boiling point of a given fluid.

[0013] Single-phase immersion cooling has a long history in cooling computer servers. In single-phase immersion cooling, there is no phase change. Instead, the liquid is heated as it circulates through the computer server and / or heat exchanger, and is then pumped back into the heat exchanger for cooling before returning to the server, thereby transferring heat away from the computer server. The fluids used in single-phase immersion cooling typically have similar requirements to those for two-phase immersion cooling, except that their boiling point is typically higher than 30-75°C to reduce losses due to evaporation.

[0014] A liquid immersion cooling system having an operating temperature range close to the ambient temperature is provided. Embodiments of the present disclosure provide a liquid immersion cooling system having a fluid for temperature control that is environmentally friendly (i.e., having a low global warming potential (GWP) and a low ozone depletion potential (ODP)) compared to a concept that does not include one or more of the features disclosed herein.

[0015] Also provided are immersion cooling methods, wherein the device is a heat-generating component, and the method includes at least partially immersing the heat-generating component in a liquid immersion cooling fluid, and using the immersion cooling fluid to transfer heat from the heat-generating component. Such devices include large-capacity energy storage devices, electrical or electronic components, mechanical components, and optical components. Examples of devices of the present disclosure include, but are not limited to, microprocessors, wafers used to manufacture semiconductor devices, power control semiconductors, power distribution switchgear, full computer servers, power electronics and transformers, circuit boards, multi-chip modules, packaged and unpackaged semiconductor devices, lasers, fuel cells, electrochemical batteries, and energy storage devices such as batteries.

[0016] In certain embodiments, the device may include electronic devices such as processors, including microprocessors. Microprocessors typically have maximum operating temperatures in the range of about 60 to 100°C, requiring effective heat transfer under conditions of high processing power, i.e., high thermal insulation. In other embodiments, the device may include energy storage systems such as batteries. When rapidly charged or discharged, batteries can reject a significant amount of heat that needs to be effectively removed to avoid overheating, internal damage, thermal runaway to adjacent batteries, and potential ignition. As these electronic and electrical devices become denser and more powerful, the amount of heat generated per unit time and per unit volume increases. Thus, the heat transfer mechanism plays a crucial role in the performance of processors or electronic / electrical components. Heat transfer fluids typically possess good heat transfer performance, good electrical compatibility (even when used in “indirect contact” applications such as those employing cooling plates), as well as low toxicity, low flammability or non-flammability, and low environmental impact. Good electrical compatibility suggests that the heat transfer fluid candidate exhibits high dielectric strength, high volume resistivity, low dielectric loss tangent, and low dielectric constant. In addition, the heat transfer fluid should exhibit good material compatibility; that is, it should not adversely affect typical constituent materials.

[0017] Perfluorinated liquids such as Fluoroinert FC-72 and FC-3284 have a dielectric constant of 2.0 or less, and approximately 10 15It is generally understood that these fluids can exhibit excellent dielectric properties, such as high volume resistivity in ohms·cm and high dielectric strength. However, these fluids are also generally associated with high GWPs that are far below the current requirements for many industrial applications. The GWP of Fluorinert FC-72 has been reported to be over 9000. Hydrofluoroethers (HFEs) have lower GWPs but are still unsatisfactory and typically have inferior dielectric properties compared to FC-72 and FC-3284. Novec 7100, for example, has a GWP of 297. Thus, there continues to be a need for working fluids for immersion cooling that meet industry dielectric applications while having a GWP below the current industry requirement, which is typically less than 150. In another embodiment, the GWP of the working fluid is less than 100. In another embodiment, the disclosed composition has a global warming potential (GWP) of 50 or less. As used herein, "GWP" is measured over a 100-year planned period for the GWP of carbon dioxide, as defined in "The Scientific Assessment of Ozone Depletion, 2002, a report of the World Meteorological Association's Global Ozone Research and Monitoring Project."

[0018] It is highly desirable that the new fluids have heat transfer characteristics such as electron surface-to-fluid thermal resistance, critical heat flux, and fluid-to-condenser thermal resistance that are equivalent to or superior to existing fluids with higher GWP, such as FC-72, FC-3284, Novec-7100, and Novec-7000. Therefore, in existing systems, they should be able to replace existing fluids without significant loss of thermal performance or the need for mechanical modifications, and in new systems designed for FC-72, FC-3284, and Novec-7100, they should be able to replace existing fluids without significant mechanical design changes. The practice of replacing existing fluids with new fluids in existing systems is often referred to as "modification."

[0019] Furthermore, it is highly desirable that the new fluids provide at least the minimum dielectric properties required for the application, or even better dielectric properties, compared to existing fluids such as FC-72, FC-3284, and HFE-7100, so that they can replace existing fluids in existing systems without significant electrical or mechanical changes, and in new systems designed for FC-72, FC-3284, and Novec-7100 without significant electrical or mechanical design changes. Desired dielectric properties include high volume resistivity, low dielectric constant, high dielectric strength, and low loss tangent.

[0020] Furthermore, these fluids should preferably be compatible with the electrical components contained within the immersion cooling system. Compatibility includes not attacking or significantly swelling any of the electrical components, and not extracting anything from any of the computer components that would degrade or impair the dielectric properties of the working fluid.

[0021] Furthermore, since these fluids have similar standard boiling points to high-GWP fluids such as FC-72, FC-3284, and Novec-7100, it is desirable that they can be used to replace high-GWP fluids in existing systems without significant mechanical or operational changes, and in new systems without significant mechanical design changes.

[0022] Most existing high-GWP fluids, such as FC-72, FC-3284, and Novec 649, are known not to be aggressive solvents for most materials used in electronic applications, and therefore do not cause excessive swelling of elastomer materials. However, while typical plasticizers are readily extracted, it is also true that the solubility of the most typical plasticizers is quite low in these fluids.

[0023] This low solubility may lead to saturation by plasticizers or mixtures of plasticizers in some fluids. As plasticizers, there are but are not limited to tris-2-ethylhexyl trimellitate, dioctyl terephthalate, diisobutyl terephthalate, N-butylbenzenesulfonamide, diethyl succinate, dimethyl succinate, diisodecyl sebacate, di-2-ethylhexyl sebacate, dibutyl sebacate, dibutyl sebacate, hexanedioic acid polymers having 2,2-dimethyl-1,3-propanediol and 1,2-propanediol isononyl ester, hexanedioic acid polymers having 1,2-propanediol octyl ester, hexanedioic acid polymers having 1,2-propanediol, acetate, tris(2-ethylhexyl) phosphate, 2-ethylhexyldiphenyl phosphate, triphenyl phosphate, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, and pentaerythritol ester of valeric acid. Acid (PETV), alkyl sulfonic acid esters containing phenol (ASE), di-C16~18 alkyl phthalates, benzyl C7~9 branched and linear alkyl phthalates, diisotridecyl phthalate, diisoundecyl phthalate, di(2-propylheptyl) phthalate, diisodecyl phthalate, diisononyl phthalate, bis(2-ethylhexyl) phthalate, diisooctyl phthalate, di-n-octyl phthalate, diisoheptyl phthalate, dicyclohexyl phthalate, diisohexyl phthalate, di-n-hexyl phthalate, di-n-pentyl phthalate, benzyl butyl phthalate, diisobutyl phthalate, di-n-butyl phthalate.Examples include di-n-propyl phthalate, diethyl phthalate, dimethyl phthalate, epoxidized soybean oil, epoxidized linseed oil, diisononylcyclohexanedicarboxylic acid, acetyl tributyl citrate, tributyl citrate, triethyl citrate, triethylene glycol dibenzoate, isodecyl benzoate, isononyl benzoate, dipropylene glycol dibenzoate, diethylene glycol dibenzoate, neopentyl glycol dibenzoate, diisodecyl azelaate, bis[2-(2-butoxyethoxy)ethyl] adipate, di-(2-butoxyethyl) adipate, di-n-butyl adipate, ditridecyl adipate, diisodecyl adipate, diisononyl adipate, di-2-ethylhexyl adipate, benzyl 2-ethylhexyl adipate, diisobutyl adipate, and glyceryl triacetate. Other contaminants besides plasticizers may include thermal paste, solder flux, and other process fluids resulting from tanks and server components, such as other extractables from polydimethyl sulfoxide.

[0024] During the operation of an immersion cooling system, when electrical components generate heat during their operation, this heat is transferred to the dielectric fluid. Although there is some circulation and dispersion of this heat by convection, the dielectric fluid directly adjacent to the components heats up rapidly, reaches its boiling point, and begins to boil. When this fluid boils on the surface of the components, the liquid flows vigorously and turns into vapor, so any dissolved plasticizers are, of course, non-volatile at the boiling point of the fluid. If the dielectric fluid is at the saturation limit of the plasticizer, this residue cannot be dissolved by the remaining dielectric fluid and therefore deposits on the available surface.

[0025] Once deposited on the surface, the residual fluid is saturated, so it does not redissolve and remains as a coating layer, slowly accumulating on the surface. Once deposited on the surface, this coating of plasticizer or a mixture of plasticizers becomes an increased heat transfer resistance, and subsequently reduces the cooling effect from the device to the fluid.

[0026] The amount of evaporated dielectric fluid is condensed by heat exchange with the coolant flowing through the condenser.

[0027] Two new dielectric fluids have been identified that have excellent dielectric properties and an appropriate boiling point to be an effective immersion cooling working fluid. These two fluids are 1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene (HFO-153-10mczz) and 1,1,1,4,5,5,5-heptafluoro-4-trifluoromethyl-2-pentene (HFO-153-10mzzy). Now, the solubility of plasticizers such as those mentioned herein has been found to be significantly and unexpectedly high in the two new dielectric working fluids, HFO-153-10mczz and HFO-153-10mzzy, as shown in Table 1. In one embodiment, the plasticizer is one or more of dioctyl terephthalate (DOTP), trioctyl trimellitate (TOTM), diisononyl phthalate, diisodecyl phthalate, and dioctyl phthalate (DOP). Solubility data for two common plasticizers, dioctyl terephthalate and trioctyl trimellitate, in HFO-153-10mczz and HFO-153-10mzzy, as well as in Novec 649 and FC-72, are shown in Table 1 below.

[0028]

Table 1

[0029] Similarly, the solubility of water has been observed to be significantly higher in HFC-153-10mczz than in either Novec 649 or FC-72. The solubility data are summarized in Table 2 below.

[0030]

Table 2

[0031] Furthermore, it was observed that the presence of plasticizers, mixtures of plasticizers, or water did not have a similarly significant adverse effect on the dielectric properties of HFO-153-10mzzy as well as HFO-153-10mczz. The dielectric constant and dielectric loss tangent data for HFO-153-10mczz and Novec 649 for comparison are shown in Table 3 below.

[0032] [Table 3]

[0033] As the data shows, the dielectric constant of HFO-153-10mczz with 72 ppm or 146 ppm of water, or 100 ppm of plasticizer, remains constant at 1.74 to 1.75 depending on the frequency. In one embodiment, the dielectric constant is less than 2.0. In another embodiment, the dielectric constant is less than 1.8. The dielectric loss tangent appears to be only slightly higher than that of the pure material, and in all cases, still lower than undiluted and dry Novec 649. Using either water saturation or 100 ppm DOTP, the dielectric loss tangent of HFO-153-10mczz is found to be less than 2.2E-03 at 20 GHz. In another embodiment, the dielectric loss tangent of HFO-153-10mczz is 2.0E-03 at 20 GHz. In yet another embodiment, the dielectric loss tangent of HFO-153-10mczz is 8.0E-03 at 20 GHz.

[0034] Novec 649 can be highly sensitive to the presence of water and other contaminants, resulting in fluid degradation and the generation of corrosive acids that can damage electronic equipment and electrical components. The inventors found that HFO-153-10mczz and HFO-153-10mzzy, on the other hand, are remarkably inert to water and other contaminants under operating conditions. Table 4 shows the results of sealed tube thermal / chemical stability tests of immersion fluids Novec 649 and HFO-153-10mczz mixed with plasticizers TOTM and DOTP in a mass ratio of 50 / 50, with 240 mmHg of air and different amounts of water up to the water solubility limit of the immersion fluid. Furthermore, metal coupons of copper, aluminum, and carbon steel were placed inside the sealed tubes and immersed in the liquid mixture of the immersion fluid and contaminants. The sealed tubes were placed in an oven at 150°C for one week. After this period, the fluid mixture was analyzed for fluoride and acidity, indicating fluid decomposition. Table 4 shows that, surprisingly, for all water concentrations, HFO-153-10mczz does not show fluoride or acidity levels exceeding the minimum detection levels of less than 0.2 ppm and 1 ppm equivalent of HCl, respectively. However, Novec 649 shows very high levels of both fluoride and acidity for all water concentrations.

[0035] [Table 4]

[0036] Embodiments of the subject matter disclosed are useful in the immersion cooling unit described below. An immersion cooling unit is provided, comprising an immersion cell defining an internal cavity. Electrical components are placed within the internal cavity and immersed in a hydrofluoroolefin working fluid that partially fills the internal cavity. A condenser is also positioned above the hydrofluoroolefin working fluid in the internal cavity, adapted and configured to condense a certain amount of evaporated hydroolefin working fluid (evaporated due to heat generation by the electrical components) through heat exchange with a cooling fluid flowing through the condenser. The dielectric working fluid is useful for immersion cooling of electrical components and is a hydrofluoroolefin working fluid comprising: a) a dielectric fluid selected from E-HFO-153-10mczz, E-HFO-153-10mzzy, or a combination of E-HFO-153-10mczz and E-HFO-153-10mzzy; and b) water and at least one of a plasticizer or plasticizer mixture dissolved in the dielectric fluid.

[0037] The immersion cooling process can be carried out according to the following steps. The immersion cooling unit described above is provided. The electrical components generate heat, thereby causing a certain amount of dielectric working fluid to evaporate. The amount of evaporated dielectric fluid is condensed by heat exchange with a coolant flowing through a condenser.

[0038] The additional steps of the immersion cooling process described above may be carried out as follows: Over a period of time, the electrical components generate heat, and a certain amount of evaporated dielectric fluid condenses. At the end of this period, the dissolved water, if present in the hydrofluoroolefin working fluid, is at a concentration of about 10 ppm to about 145 ppm, and the dissolved plasticizer or plasticizer mixture, if present in the hydrofluoroolefin working fluid, is at a concentration of about 10 to about 7341 ppm.

[0039] Additional Embodiments A1. A hydrofluoroolefin working fluid useful in immersion cooling, A dielectric fluid selected from the group consisting of E-HFO-153-10mczz, E-HFO-153-10mzzy, and combinations thereof, The dielectric fluid contains at least one of water and a plasticizer or a mixture of plasticizers, A hydrofluoroolefin working fluid containing this fluid.

[0040] A2. A hydrofluoroolefin working fluid useful in immersion cooling, A dielectric fluid consisting of E-HFO-153-10mczz, The dielectric fluid contains at least one of water and a plasticizer or a mixture of plasticizers. A hydrofluoroolefin working fluid containing this fluid.

[0041] A3. A hydrofluoroolefin working fluid useful in immersion cooling, A dielectric fluid consisting of E-HFO-153-10mczz, The dielectric fluid contains at least one of water and a plasticizer or a mixture of plasticizers. Hydrofluoroolefin working fluids are essentially derived from this.

[0042] A4. A hydrofluoroolefin working fluid useful in immersion cooling, A dielectric fluid consisting of E-HFO-153-10mzzy, The dielectric fluid contains at least one of water and a plasticizer or a mixture of plasticizers. A hydrofluoroolefin working fluid containing this fluid.

[0043] A5. A hydrofluoroolefin working fluid useful in immersion cooling, A dielectric fluid consisting of E-HFO-153-10mzzy, The dielectric fluid contains at least one of water and a plasticizer or a mixture of plasticizers. Hydrofluoroolefin working fluids are essentially derived from this.

[0044] A6. A hydrofluoroolefin working fluid useful in immersion cooling, A dielectric fluid selected from E-HFO-153-10mczz and / or E-HFO-153-10mzzy, The dielectric fluid contains at least one of water and a plasticizer or a mixture of plasticizers. Hydrofluoroolefin working fluids are essentially derived from this.

[0045] A7. The hydrofluoroolefin working fluid according to any one of Embodiments A1 to A6, wherein the dissolved plasticizer or plasticizer mixture present in the working fluid is one or more of bis(2-ethylhexyl) terephthalate, tris(2-ethylhexyl) trimellitate, diisononyl phthalate, diisodecyl phthalate, and bis-2-ethylhexyl phthalate.

[0046] A8. A hydrofluoroolefin working fluid according to any one of Embodiments A1 to A7, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid at a concentration of about 10 to about 7341 ppm.

[0047] A9. A hydrofluoroolefin working fluid according to any one of Embodiments A1 to A8, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid at a concentration of about 10 to about 7000 ppm.

[0048] A10. A hydrofluoroolefin working fluid according to any one of Embodiments A1 to A9, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid at a concentration of about 10 to about 6000 ppm.

[0049] A11. A hydrofluoroolefin working fluid according to any one of Embodiments A1 to A10, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid at a concentration of about 10 to about 5000 ppm.

[0050] A12. A hydrofluoroolefin working fluid according to any one of Embodiments A1 to A11, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid at a concentration of about 10 to about 4000 ppm.

[0051] A13. A hydrofluoroolefin working fluid according to any one of embodiments A1 to A12, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid at a concentration of about 10 to about 3000 ppm.

[0052] A14. A hydrofluoroolefin working fluid according to any one of Embodiments A1 to A13, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid at a concentration of about 10 to about 2000 ppm.

[0053] A15. A hydrofluoroolefin working fluid according to any one of Embodiments A1 to A14, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid at a concentration of about 10 to about 1000 ppm.

[0054] A16. A hydrofluoroolefin working fluid according to any one of Embodiments A1 to A15, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid at a concentration of about 10 to about 500 ppm.

[0055] A17. A hydrofluoroolefin working fluid according to any one of embodiments A1 to A16, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid at a concentration of about 10 to about 250 ppm.

[0056] A18. A hydrofluoroolefin working fluid according to any one of embodiments A1 to A17, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid at a concentration of about 10 to about 100 ppm.

[0057] A19. A hydrofluoroolefin working fluid according to any one of embodiments A1 to A18, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid at a concentration of more than 46 ppm to about 7341 ppm.

[0058] A20. A hydrofluoroolefin working fluid according to any one of Embodiments A1 to A19, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid at a concentration of more than 46 ppm to about 7000 ppm.

[0059] A21. A hydrofluoroolefin working fluid according to any one of Embodiments A1 to A20, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid at a concentration of more than 46 ppm to about 6000 ppm.

[0060] A22. A hydrofluoroolefin working fluid according to any one of Embodiments A1 to A21, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid at a concentration of more than 46 ppm to about 5000 ppm.

[0061] A23. A hydrofluoroolefin working fluid according to any one of Embodiments A1 to A22, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid at a concentration of more than 46 ppm to about 4000 ppm.

[0062] A24. A hydrofluoroolefin working fluid according to any one of Embodiments A1 to A23, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid at a concentration of more than 46 ppm to about 3000 ppm.

[0063] A25. A hydrofluoroolefin working fluid according to any one of Embodiments A1 to A24, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid at a concentration of more than 46 ppm to about 2000 ppm.

[0064] A26. A hydrofluoroolefin working fluid according to any one of Embodiments A1 to A25, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid at a concentration of more than 46 ppm to about 1000 ppm.

[0065] A27. A hydrofluoroolefin working fluid according to any one of embodiments A1 to A26, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid at a concentration of more than 46 ppm to about 500 ppm.

[0066] A28. A hydrofluoroolefin working fluid according to any one of Embodiments A1 to A27, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid at a concentration of more than 46 ppm to about 250 ppm.

[0067] A29. A hydrofluoroolefin working fluid according to any one of Embodiments A1 to A28, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid at a concentration of more than 46 ppm to about 100 ppm.

[0068] A30. A hydrofluoroolefin working fluid according to any one of Embodiments A1 to A29, wherein the dissolved water is present in the working fluid at a concentration of more than 10 ppm to approximately 145 ppm.

[0069] A31. A hydrofluoroolefin working fluid according to any one of Embodiments A1 to A30, wherein the dissolved water is present in the working fluid at a concentration of more than 10 ppm to about 100 ppm.

[0070] A32. A hydrofluoroolefin working fluid according to any one of Embodiments A1 to A31, wherein the dissolved water is present in the working fluid at a concentration of more than 10 ppm to about 75 ppm.

[0071] A33. A hydrofluoroolefin working fluid according to any one of Embodiments A1 to A32, wherein the dissolved water is present in the working fluid at a concentration of more than 10 ppm to about 50 ppm.

[0072] A34. A hydrofluoroolefin working fluid according to any one of Embodiments A1 to A33, wherein the dissolved water is present in the working fluid at a concentration of more than 20 ppm to approximately 145 ppm.

[0073] A35. A hydrofluoroolefin working fluid according to any one of embodiments A1 to A34, wherein the dissolved water is present in the working fluid at a concentration of more than 20 ppm to about 100 ppm.

[0074] A36. A hydrofluoroolefin working fluid according to any one of Embodiments A1 to A35, wherein the dissolved water is present in the working fluid at a concentration of more than 20 ppm to about 75 ppm.

[0075] A37. A hydrofluoroolefin working fluid according to any one of embodiments A1 to A36, wherein the dissolved water is present in the working fluid at a concentration of more than 20 ppm to about 50 ppm.

[0076] A38. A hydrofluoroolefin working fluid according to any one of embodiments A1 to A37, wherein the dielectric constant is less than approximately 2.0.

[0077] A39. A hydrofluoroolefin working fluid according to any one of embodiments A1 to A38, wherein the dielectric constant is less than approximately 1.8.

[0078] A hydrofluoroolefin working fluid according to any one of embodiments A1 to A39, having a dielectric loss tangent of less than approximately 8.0E-03 at 40.20 GHz.

[0079] A hydrofluoroolefin working fluid according to any one of embodiments A1 to A40, having a dielectric loss tangent of less than approximately 2.5E-03 at 1.20 GHz.

[0080] A42. Immersion cooling unit, An immersion cell that defines the internal cavity, The electrical components in the internal cavity, A hydrofluoroolefin working fluid partially fills the internal cavity, and the electrical component is at least partially immersed in it. A condenser positioned above the hydrofluoroolefin working fluid in the internal cavity and adapted and configured to condense a certain amount of the hydrofluoroolefin working fluid that can be evaporated by heat generated by the electrical components, wherein the hydrofluoroolefin working fluid is the hydrofluoroolefin working fluid described in any of embodiments A1 to A41; A liquid immersion cooling unit equipped with the following features.

[0081] A43. Immersion cooling process, The steps include providing the liquid immersion cooling unit described in Embodiment A42, The steps include generating heat in the electrical component and thereby evaporating a certain amount of dielectric fluid, The process involves condensing a certain amount of the evaporated dielectric fluid by heat exchange with a coolant flowing through the condenser, A process that includes this.

[0082] A44. The immersion cooling process according to Embodiment A43, further comprising the step of performing each of the steps of generating heat in an electrical component and condensing a certain amount of evaporated dielectric fluid over a period of time, wherein at the end of the period, the dissolved water is at a concentration of about 10 ppm to about 145 ppm if present in the hydrofluoroolefin working fluid, and the dissolved plasticizer or plasticizer mixture is at a concentration of about 10 to about 7341 ppm if present in the hydrofluoroolefin working fluid.

Claims

1. A hydrofluoroolefin working fluid useful in immersion cooling, A dielectric fluid selected from the group consisting of E-HFO-153-10mczz, E-HFO-153-10mzzy, and combinations thereof, A hydrofluoroolefin working fluid comprising water and at least one plasticizer or plasticizer mixture dissolved in the dielectric fluid, wherein the dissolved water has a concentration of about 10 ppm to about 145 ppm when present, and the dissolved plasticizer or plasticizer mixture has a concentration of about 10 to about 7341 ppm when present.

2. A hydrofluoroolefin working fluid useful in immersion cooling, A dielectric fluid consisting of E-HFO-153-10mczz, A hydrofluoroolefin working fluid comprising water and at least one plasticizer or plasticizer mixture dissolved in the dielectric fluid, wherein the dissolved water has a concentration of about 10 ppm to about 145 ppm when present, and the dissolved plasticizer or plasticizer mixture has a concentration of about 10 to about 7341 ppm when present.

3. A hydrofluoroolefin working fluid useful in immersion cooling, A dielectric fluid consisting of E-HFO-153-10mczz, A hydrofluoroolefin working fluid, essentially comprising water and at least one plasticizer or plasticizer mixture dissolved in the dielectric fluid, wherein the water, if present, is at a concentration of about 10 ppm to about 145 ppm, and the plasticizer or plasticizer mixture, if present, is at a concentration of about 10 to about 7341 ppm.

4. A hydrofluoroolefin working fluid useful in immersion cooling, A dielectric fluid consisting of E-HFO-153-10mzzly, A hydrofluoroolefin working fluid comprising water and at least one plasticizer or plasticizer mixture dissolved in the dielectric fluid, wherein the dissolved water has a concentration of about 10 ppm to about 145 ppm when present, and the dissolved plasticizer or plasticizer mixture has a concentration of about 10 to about 7341 ppm when present.

5. A hydrofluoroolefin working fluid useful in immersion cooling, A dielectric fluid consisting of E-HFO-153-10mzzly, A hydrofluoroolefin working fluid, essentially comprising water and at least one plasticizer or plasticizer mixture dissolved in the dielectric fluid, wherein the dissolved water, if present, has a concentration of about 10 ppm to about 145 ppm, and the dissolved plasticizer or plasticizer mixture, if present, has a concentration of about 10 to about 7341 ppm.

6. A hydrofluoroolefin working fluid useful in immersion cooling, A dielectric fluid selected from E-HFO-153-10mczz and / or E-HFO-153-10mzzy, A hydrofluoroolefin working fluid, essentially comprising water and at least one plasticizer or plasticizer mixture dissolved in the dielectric fluid, wherein the dissolved water, if present, has a concentration of about 10 ppm to about 145 ppm, and the dissolved plasticizer or plasticizer mixture, if present, has a concentration of about 10 to about 7341 ppm.

7. The hydrofluoroolefin working fluid according to any one of claims 1 to 6, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid and is one or more of bis(2-ethylhexyl) terephthalate, tris(2-ethylhexyl) trimellitate, diisononyl phthalate, diisodecyl phthalate, and bis-2-ethylhexyl phthalate.

8. The hydrofluoroolefin working fluid according to any one of claims 1 to 7, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid at a concentration of about 10 to about 2000 ppm.

9. The hydrofluoroolefin working fluid according to any one of claims 1 to 8, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid at a concentration of about 10 to about 1000 ppm.

10. The hydrofluoroolefin working fluid according to any one of claims 1 to 9, wherein the dissolved water is present in the working fluid at a concentration of about 10 ppm to about 100 ppm.

11. The hydrofluoroolefin working fluid according to any one of claims 1 to 10, wherein the dissolved plasticizer or plasticizer mixture is present in the working fluid at a concentration of about 10 to about 50 ppm.

12. A hydrofluoroolefin working fluid according to any one of claims 1 to 11, wherein the dielectric constant is less than approximately 2.

0.

13. A hydrofluoroolefin working fluid according to any one of claims 1 to 12, wherein the dielectric constant is less than approximately 1.

8.

14. A hydrofluoroolefin working fluid according to any one of claims 1 to 13, having a dielectric loss tangent of less than approximately 8.0E-03 at 20 GHz.

15. A hydrofluoroolefin working fluid according to any one of claims 1 to 14, having a dielectric loss tangent of less than approximately 2.5E-03 at 20 GHz.

16. Immersion cooling unit, An immersion cell that defines the internal cavity, The electrical components in the aforementioned internal cavity, The working fluid partially filling the internal cavity, A condenser disposed above the working fluid in the internal cavity, wherein the working fluid at least partially immerses the electrical components, and the working fluid is a hydrofluoroolefin working fluid according to any one of claims 1 to 15; A liquid immersion cooling unit equipped with the following features.

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